1982 gpz 750 cylinder question

hi i just picked up a 82 750 gpz, looks like one of the rings broke and messed up the cylinder wall, is this the same cylinder as the other 750's? i went on to kawasaki.com and they all have the same part number, did they all have the same bore size for the gpz and the standard 750? also i measured the piston, it measures 68.64 mm above the compression ring, it also has numbers stamped in it, so i was wondering if someone could help me tell how over sized it is. its marked F6318 4186PS XC. if someone has the stock sizes or where to find them, my manual only shows bore and stroke and compression ratio.

I think you have to measure lower down near the bottom of the piston skirt to get the true diameter, up where the rings are it is significantly narrower.

The over sizes go in steps of 0.25mm (.010") from stock to a max of 1.00mm.

Sorry, I don't have a manual for the four so I don't have the nominal spec. It is in the FSM, so you might try the reference stickies here to see if somebody linked to one.

thanks, i did some looking around late last night and i think i found the 4186ps is a part number for the wisco 810 kit, the piston in the kit measures 69.0 mm so maybe i got lucky buying this very cheap with a 810 kit

The problem being, if the bore is messed up and you are already at the 810 kit, they don't make an oversize 810. So, it may be possible to resleeve and bore the cylinders or perhaps get another set of jugs and bore to size.